Fluid compressor



C. B. VAN HORN.

FLUID COMPRESSOR. APPLICATION FILED .IUNE"30. I9I9.

3mm/whoa L QM eoe. a?. cmfmn PIM/gw# UNITED STATES PATENT OFFICE.

CHARLES B. VAN HORN, 0F DETROIT, MICHIGAN.

' FLUID comrnnsson.

'Application inea June ao,v 191s. serial No. 307,609.

T0 all whom it may concern:

Be it known that I, CHARLES B. VAN HoRN,a citizen of the United States of America, residing at Detroit, in the county vented certain new and useful Improvements in Fluid Compressors, of which the following is a specification, reference being had therein to the accompanying drawings.

This invention relates to fluid pumps or compressors and more particularly to mechanism for operating the pistons thereof. The object` of the invention is to reduce side thrust of the connecting rods upon the pistons and to so connect the cranks of two pistons that the power of both cranks will be applied to each working stroke of each piston, thus applying load to each crank throughout its rotation and reducing vibration and consequent noise and wear.

A further ob]ect is to provide a construction having certain `other new and useful features, all as hereinafter more fully described.

With these and other ends in View, the invention consists in the matters hereinafter set forth, and more particularly pointed out in the` appended claims, reference being had to the drawings in which Figure 1 is a longitudinal vertical section through a device illustrative of anV application of the invention, and

Fig. 2 is la transverse vertical section through the same, substantially upon the line II-II of Fig. 1.

`It is the usual practice to connect pistons to their cranks by continuous connecting rods but such connectionputs a heavy side thrust on the pistons, due to the angular movement of the connecting rods' relative to the plane of movement of the pistons. This side thrust causes the pistons and cylinders to wear and causes vibration, and one of the objects of this invention is to provide a construction wherein that portion of the connecting rod which is connected to its piston, will move substantially in the vertical plane of the axis of the piston and which mechanism for operating a pair of pistons, will connect the cranks for such pistons in such a manner that lthe power of both cranks will be applied for operating each piston in both directions of its reciprocating movement.

In the drawing, a pump construction particularly adapted for creating fluid pressures in small refrigeratin apparatuses is show whichpump is provi ed with a pair of cylinders and pistons therein operated by mecha- .nism embodying the invention. of Wayne and State of Michigan, have iny While a particular pump construction is shown, it will be understood that the invention may be applied to other constructions and to other devices having cylinders and pistons Vtherein operated by cranks. It will therefore be understood that the construction and arrangement shown is merely illustrative of the invention. f

In wthe drawing, 1 indicates a. suitable crank case and 2 a pair of cylinders arranged in parallelism and spaced relation, said cylinders bein formed integral with or otherwise secure `to the top of the crank case 1. In rthe cylinders are pistons 3 of any suitable construction and mounted in suitable bearings in the crank case, are crank shafts 4, each having a' crank 5 which is connected to the piston by a connecting rod and pitman, each; connecting rod beingpivotally attached at its upper end to the piston in any suitable manner, as by a pin 7 and the pitman 8 being attached to its crank by the usual bearin 9 or in an other suitable manner.` The adjacent en s of the connecting rod-and pitman are pivotally attached to one end of a rocker barA 10 which is supported intermediate its ends by a fixed pivwith a downwardly extending arm or offset 13 to which the upper ends of the pitmen 8 are pivotally attached by the pivots 14C, the plane passing through the axes of these pivots being below the plane passing through the axis of the pivots 12 and the pivotal support 11. It has beenl found by experiment that the various elements will function properly when the distance between the axes of the crank shafts 4--4 is the same as the distance between the centers of the pivots 12, the distance in each case being four times the total throw of the crank 5. The axis of the pivotal support 11 lies at a distance from the plane passing through the axes of the crank shafts #1 -l1 equal to five times the total throw of the crank. It is in a plane at right angles to the plane of the axes v-t and midway between them. The distance from the center of the pivot 12 to the center of the pvot 14 is three-fourths the total throw of the crank. Variations from these proportions will result in binding at the pivotal connections or total inoperativeness.

Power may be applied to the crank shafts 4 to simultaneously turn the same in opposite directions, in any suitable manner and the cranks of these crank shafts are arranged in opposed relation so that when one piston is up the other is down, thus giving a b`alanced reciprocating motion to the two pistons.

As shown, suitable means is provided for supplying power to the crank shafts and driving the same at a reduced speed from the speed of the driving shaft, said crank shafts being preferably in the form of two` parallel gears 15 spaced apart and connected y the crank or wrist pin 5, the gears having axial integral stubs forming the ends of the crank shaft, which ends engage suitable bearings in the sides of the crank case. Upon a suitable intermediate shaft 16, extending across the crank case, is mounted a pinion 1T in mesh with the gears 15 of the two crank shafts and on this shaft 16 is also secured a gear 18 which is in mesh with a pinion 19 D on the driving shaft 20 which extends into the casing through a suitable bearing 21 on the side wall thereof. A train of reduction .gearing is thus provided for turning the crank shafts simultaneously in opposite directions and at a speed which is much less than the speed of the -driving shaft.

The two connecting rods for the pair of pistons are connected by't'he rocker bar which is pivotally supported midway between the vertical transverse planes of the two cylinders and power will be applied by both cranks equally torock the rocker bar. In a single acting pump construction, the suction or down-stroke requires but little power while the up-stroke compresses the fluid and requires an amount of power dependingv upon the compression produced. There is, therefore, a practically idle stroke for each pistonand by connecting the pistons up through the medium of the rocker bar, the power required for the compression stroke of each piston will be supplied by both cranks and therefore resistance to the turning movement of both cranks will be continuous and not intermittent as where each crank is separately connected to its piston. Vibration and consequent wear is therefore greatly reduced by thus connecting up by means of a rocker bar, the conmeeting rods of a pair of pistons. Furthermore, in a gas compression system, the gas flows in a closed circuit, and returns to the pump with considerable pressure. The gas at the intake Valve exerts pressure on the piston as it is drawn into the cylinder. lhen the pistons are operated by connecting rods attached to a rocker bar, this pressure of the incoming gas is utilized to assist in the compression of the gas in the other cylinder, which causes a balancing of pressures that aids in the smooth running of the machine` besides reducing the power required. The upper members 6 of the connecting rods being pivotally connected to the ends of the rocker bar in the plane of the axis of the pivotv` upon turning movement of the rocker for reciprocating` the pistons in opposite directions, the lower ends of these parts of the connecting rods will swing laterally to only a slight degree due to the large arc which the pivots 12 describe about the axis 11, and the upper ends of the parts 8 of the connecting rods are given a lateral swinging movement by being connected to the rocker bar at a point below the plane of the pivots 11 and 12 so that the angular thrust of these lower end portions will not be excessive due to their short length and dead centers are eliminated. A compressor constructed as described has proved to be remarkably free from vibration and very noiseless in its operation. rThe power required heilig so eiliciently applied, a smaller motor can be used than is customary in similar mechanisms hitherto employed.

The construction providesa very simple and compact construction particularly adapted as a compressor for small refrigerating plants and in which the reduction gearingis all enclosed -within the crank case free from dust and dirt and where it may run in oil to prevent noise and wear. Obviously, changes may be made in the con struction and arrangement of parts within the scope of the appended claims and 1 do not, therefore, limit myself to the particular arrangement shown.

Having thus fully described my invention, what I claim is:

1. The combination of a pair of cylinders, pistons in said cylinders, a pair of cranks for operating the pistons, connecting rods and pitmen for connecting the cranks with the pistons, and a member pivotally supported intermediate the axes of the two cylinders with its ends forming a pivotal connection between said rods and pitmen.

2. The combination of a pair of cylinders. pistons in said cylinders, a pair of cranks for operating the pistons, a pair of connecting rods, a pair of pitmen and a member pivotally supported intermediate its ends and to the ends of which the adjacent ends of the connecting rods and pitmen are pivotally attached.

3. The combination of a pair of cylinders spaced apart and in parallel relation, pistons in the cylinders,'cranks for operating the pistons, a connecting rodand a pitman for connecting each crank with its piston, and a rocker bar pivotally supported intermediate its ends and forming at each end a pivotal connection between a connecting rod and a pitman.

4. The .combination of a pair of cylinders spaced apart and in parallel relation, pistons in said cylinders, cranks for operating the pistons, a connecting rod and a pitman connecting each crank with its piston, and a rocker bar pivotally supported intermediate its ends with the connecting rods, pivotally attached to the ends of said rocker bar in the plane of the axis oits pivotal support and the pitmen pivotally Aattached to the ends of said rocker bar at points distant from the points of the pivotal attachment of the connecting rods thereto.

5. The combination of a pair of vertically disposed cylinders spaced apart and in parallel relation, pistons in said cylinders, cranks for operating the pistons, a connecting rod and a pitman for connecting each crank with its piston, and a rocker bar pivotally supported intermediate its ends and to the ends of which the adjacent ends of the rods and pitmen are pivotally attached, the axis of the pivotal attachment of the connecting rods to the ends of said rocker bar being in the plane of the axis of the pivotal support of said bar and the plane of thel axis of the vpivotal attachment of the itmen to said bar, being below and at a istance from said plane passing through the axis of the pivotal support of said bar.

6. The combination of a crank case, vertically extending cylinders on said crank case, pistons in said cylinders, cranksfor operating the pistons mounted in they crank case, connecting rods and pitmen connecting the cranks to the pistons, a rocker bar pivotally supported intermediate its ends upon the crank case and to the ends of which the adjacent ends of the connecting rods and pitmen are pivotally attached, and gearing within the crank case for imparting simultaneous rotation to said cranks.

7. The combination of a crank case, vertically extending parallel spaced cylinders on the crank case, pistons in the cylinders, cranks in lthe crank case, connecting rods and pitmen connecting the cranks and pistons, a rocker bar pivotally supported intermediate its ends upon the crank case with the adjacent ends of the connecting rods and pitmen pivotally attached to the ends of the rocker bar, a drive shaft extending into the crank case between the vertical planes of the axis of the cranks and gearing within the crank case for transmitting simultaneous rotation to the cranks at a reduction of Speed.

In testimony whereof I afix my signature in the presence of two witnesses.

CHARLES B. VAN HORN. Witnesses: f ANNA M. Donn,

Criss. W. STAUFFIGER. i 

